MacAngus, I see you have been applying a DxO Film Pack profile (generic Velvia). It might be the cause of the grain that appears on the supplied cropped image.
You can apply film profiles selectively in DxO (colour and/or grain). If you are only interested in simulating film colour and don't want to have film grain applied to the image, you should uncheck that latter option in the
DxO Film Pack adjustment section. I believe the control is called
DxO Film Pack Grain. You might want to check that it has been turned off in your case.
As for the fly, it is probably dirt on the sensor. I once had a midge in Scotland that ended its life in my camera. It entered there while I was switching lenses. The poor creature never reached the Velvia roll that was in there since it had its head chopped off by the shutter. After a day of constant harrassment by midges, I must admit I almost enjoyed it - until I had to clean the mess it did on the shutter.
Cheers,
Fabien